Our backs weren’t designed for the modern sedentary lifestyle. Anthropologists believe that early humans were bipeds (walked upright), but also spent time on all four limbs. After examining the skeletons of prehistoric species, they think the spinal structure changed as human beings stood for longer periods. The lower spine curved more and more over the eons. That curve, the lordosis, supports upper body weight better than the straight spine of much earlier primates that walked on all fours.
Does a more curved lower spine help us deal better with life as an upright but often seated creature? In fact, just the opposite is the case. While increased curvature of upper or lower spine does handle the weight of the upper body on the pelvis, the benefits of a slightly curved spine end at a certain point. Complications of poor posture and obesity tend to offset the stabilizing design. Perhaps further modifications over eons will help us to live life seated. No one is sure. Nonetheless, maintenance of the natural “S” curve is essential to good back health.
S.O.S: Save our “S”
The spine is naturally configured in an “S” curve from the side. A slight concave curve of the cervical spine (neck) gently changes to the longer convex thoracic (chest) area ending in a concave curve of the lumbar region. The neutral “S” curving cervical, thoracic and lumbar spine is also the most stress-free state. Yet, due to everyday demands, not even from lifting heavy objects, but just by driving, standing or sitting at a desk for hours at a time, our spine strays from the comforting “S.” The neck and mid-back suffer as we slouch forward or bend the wrong way repeatedly. One day, our back is abused just once too often. Picking up a crumpled piece of paper that didn’t make it into the trash brings on a sudden twinge of pain. Our back reminds us that it is there and demands our attention.
The back is the spinal vault
Like the brain protected by the skull (a fusion of several bones), bones called vertebrae surround the spinal cord. The highway from brain to limbs, the spinal cord carries information about our world and our intentions – both voluntary and automatic. The index finger tip touches the stove, senses that it’s hot and generates a signal that travels up the median nerve to the brachial plexus (grouping of nerves near the axilla or armpit) to the cervical spine and then to the brain. Our sense of touch is processed and the brain generates an impulse that travels down the spine from nerve-to-nerve, and in a lightning flash, we withdraw the finger.
A vulnerable vault
The back does a fine job of protecting the delicate spinal cord. Why is it prone to injury? Unlike the skull, the back must maintain flexibility while providing bony protection for the spinal cord. Bending and twisting of bone over bone is only possible with specialized structures called vertebrae and their supporting muscles and ligaments. These components work together, but each is subject to its own share of problems.
Muscles and ligaments
Back muscles are the most frequently injured structures because they are already working very hard to maintain the “S” curve. Bending too far, or the tendency to overextend with a poor posture, puts more strain on back muscles. Eventually, whole regions of back muscles tighten. Continued demand on tight, tired muscles leads to the injury and pain of a muscle strain, or even a torn ligament when the attachment of muscle to bone gives way.
Each vertebra is made up of a body and arch. The vertebral body houses a spongy central disc that allows for movement of the vertebra above and below. Behind each vertebral body, the spinous process contains a portion of the spinal cord, which runs continuously above, and below, opening up into nerve roots that converge again to form major peripheral nerves.
In spite of their complex design, the vertebrae cannot handle life’s forces without the help of the back muscles and ligaments. When an area of muscle weakens, the stress is transferred to the closest vertebrae at the ligament, which surrounds the disc. Eventually, the ligament gives way and the disc slips forward onto the spine or nerve roots.
The spinal cord
So why make us carry a “vault” on our back? All the armor of the vertebrae (bones), muscles and ligaments serves to protect the spinal cord, a delicate, whitish gray vertical tube. The spinal cord is composed mainly of myelin, a fatty substance that insulates nerve fibers. Nerve cells and other nutrient-supplying cells gather in clusters to receive and transmit impulses from the brain and out to the rest of the body and back. Your back is an intricate structure, giving you the power to stand, walk, run, sit and lift. The ligaments of the lower back connect the vertebral bones, supporting and stabilizing this area. An unconditioned back is prone to strain when muscles and ligaments are overworked. Back muscle strain occurs when a sudden, forceful movement injures a ligament, which has become stiff or weak from poor conditioning or overuse. Acute lower back pain is a common medical problem afflicting two-thirds of Americans during some part of their lives. Each year nearly 6 million Americans suffer from back or spinal problems, making back pain the most commonly reported health condition in the United States.
The back is made up of bones, muscles and other tissues extending from the neck to the pelvis. The spinal column supports the body’s trunk and protects the spinal cord – the vast highway of nerves that help control the body’s sensations and nerves. Bones in your back include 30 pieces stacked up called vertebrae.
This is your spine, and vertebrae protect the spinal cord. Nerves from the spinal cord branch off to organs and muscles throughout the body. The spaces between the vertebrae are made up of round spongy pads of cartilage. These are the intervertebral discs that act as shock absorbers when you walk or run. Ligaments and tendons hold the vertebrae in place and attach muscles to the spinal column.
Lower back pain can be anything from a lumbar sprain to an actual rupture of a disc. However, most cases of lower back pain come from muscle or ligament strain as a result of lifting, bending or overstretching. As a result of the injury, your back muscles spasm, causing the muscles to “lock” and develop pain. Acute back pain usually means you have pain for a few days to a few weeks. Chronic pain lasts for three months or more. Chronic pain or pain with unusual symptoms could mean a tumor, herniated disc, osteoporosis, osteoarthritis or other serious diseases.
In more than 95 percent of cases, the underlying cause is not serious. Using over-the-counter pain relievers such as ibuprofen, aspirin or naproxen for a few days usually help you feel better. Through exercise and healthy habits, you can keep your back healthy and strong and even avoid pain in the future. The News